Lego and model railroads, parts ID please

[W124Bob]

Came across this and want to replicate it, but can anyone help with the Lego parts to be more specific than "gear reducer". I dont really need any more than is shown.
https://youtu.be/Z_uJ9tmEdVk
https://youtu.be/ArUu6HEl28k

[W124Bob]

Cheers, bookmarked.